Imagine simply shining a light on your skin to determine how much sugar is in your blood. Researchers at MIT are developing a glucose-monitoring device for diabetes patients that may help do away with finger pricks.

By scanning a user's arm or finger with near-infrared light, the device frees users from the necessity of drawing blood, a daily routine for most type 1 diabetes patients.

The laptop-size machine is the result of 15 years of research at the MIT Spectroscopy Lab. It employs Raman spectroscopy, which can determine chemical compounds based on their molecular vibration.

In a technique described in an Analytical Chemistry paper, the researchers fire near-infrared light into the skin. It only penetrates about half a millimeter, reaching the interstitial fluid surrounding skin cells, but not the blood itself.

While glucose is represented in the interstitial fluid, there's a delay of up to 10 minutes between the time it spikes in the bloodstream (after someone consumes sugary food, for example) and the time it surges in the fluid.

The researchers developed an algorithm that lets them predict blood glucose based on measurements of interstitial fluid glucose, as well as a calibration method that takes into account the rate at which glucose hits the fluid.

The team has done a small study on human volunteers, and plans another study this fall. The effort is one of many using techniques such as spectroscopy and ultrasound to check glucose without breaking the skin. Earlier this year, in fact, MIT engineers also announced work on designing carbon nanotubes that can be injected beneath the skin to reveal continuous blood glucose levels in real time--kind of like a high-tech tattoo.

About the author

Crave freelancer Tim Hornyak is the author of "Loving the Machine: The Art and Science of Japanese Robots." He has been writing about Japanese culture and technology for a decade. E-mail Tim.
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